NOTES AND ABSTRACTS. 
501 
Of these three with highest percentage he says : "I consider them to be due 
to Mendelian segregation." 
Nevertheless they fall short of the necessary 25 per cent. " This is due to 
the difficulties of cultivation and to less viability of the dwarfs as compared with 
the normal specimens. I chose the one with 17-8 per cent, for continuing the 
experiment. I succeeded in having a dozen of plants flower and ripen their 
seeds as annuals." 
Table IV. gives us the results. Three have either 1 or 2 ; while seven had 
dwarfs ranging from 25 to 57, the average percentage being 22 per cent. This 
is not far from the required number 25. A question arises, why were there so 
few dwarfs in the first two experiments, viz. 1 and 2 only with two figures, while 
in the third the number rose to 7 ? 
As annuals are normally, i.e. when wild, far more prolific than biennials and 
perennials, may not this increase of dwarfs be due to their greater fertility, 
as the seven were derived direct from annuals ? — G. H. 
Orchard Spraying Experiments. By J. C. Blair and others (U.S.A. Exp. Stn., 
Illinois, Bull. 185, 212 pp. ; 10 plates). — A long and careful account of trials with 
various spray-fluids in field trials. — E.A.Bd. 1 
Paeonia Willmottiae (Bot. Mag. t. 8667). — China. Nat. Ord. Ranunculaceae, 
tribe Paeonieae. Herb, perennial. Leaves twice-ternate, 6 inches long, 3 
inches wide. Flowers, 6 inches across. Petals, about 10, pure white. — G. H. 
Pandanus furcatus (Bot. Mag. t. 8671). — India. Nat. Ord. Pandanaceae. Tree, 
10-13, rarely to 30 feet high, sparingly branched. Leaves linear, 10-16 feet long, 
2-4 inches wide, with marginal spines. Male inflorescence terminal, pendulous. 
Female spadix solitary. Cone oblong, 6-18 inches long, orange-brown, fleshy. 
G. H. 
Parsley Disease. By J. A. McClintock (U.S.A. Exp. Stn:, Virginia, Bull. 18, 
Jan. 1916, pp. 379-384 ; 3 figs.). — This disease is caused by Sclerotinia Libertiana 
which has already been described by Hall and Stevens in 1910. 
The control measures suggested are steam sterilization of the soil and a suitable 
rotation of crops. Drenching the soil with a watery solution of formaldehyde 
is useful for single-beds and frames in which the plants are but lightly attacked. 
A. B. 
Pathology of Ornamental Plants. By Mel. T. Cook (Bot. Gaz. lxi. p. 67, 
1916) . " Though the literature on diseases of field crops, fruits, and vegetables is 
extensive, that on the diseases of ornamental plants is very meagre." The author 
observes that this neglect is due to three causes: " (1) The supposition that 
they are of no economic importance ; (2) Growers have received little or no 
satisfaction from plant pathologists ; (3) The latter find the work with ornamental 
plants unsatisfactory and complicated by physiological problems which make the 
returns uncertain." 
In reply he observes : " (1) The growing of ornamental plants is of very great 
importance and involves millions of dollars annually ; (2) The pathologists are 
insufficiently informed ; (3) Of outdoor work little is as yet known beyond the 
treatment of Chrysanthemum diseases. The indoor problems are by far the 
most complicated and the most difficult, and are not yet attacked. — G. H. 
Peach Cankers and their Treatment. By R. A. Jehle (U.S.A. Exp. Stn., 
Cornell, Cir. No. 26, Sept. 1914, pp. 52-62 ; 8 plates). — Cankers are prevalent on 
all varieties of peach trees, and may be found on the wood of all ages from the 
trunk of the tree to the growth of the current year. Two types of cankers occur, 
brown-rot canker and frost cankers. 
Brown-rot canker is caused by a fungus (Sclerotinia fructigena) which produces 
a brown rot in the fruit and which may pass down the twig into the tree. The 
fungus now spreads in all directions, and the bark cracks and splits with a copious 
exudation of gum. Ultimately a canker is formed, which may persist from year 
to year. 
Frost cankers are usually found on the main trunk, near the surface of the 
soil, and appear as slight depressions in the bark. No growth takes place at 
these points, and, like the cankers produced by Sclerotinia fructigena, a copious 
gum flow occurs during wet weather. 
The control measures suggested are the destruction of all affected blossoms, 
fruits, and twigs, and the smearing of gas tar upon the open wounds on the 
trees. — A. B. . 
